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Metabolic and functional changes in the heart during prolonged hypothermia.

https://arctichealth.org/en/permalink/ahliterature298768
Source
Arctic Aeromedical Laboratory. Alaskan Air Command. Fort Wainwright, Alaska. Technical documentary report, TDR-64-4. 9 p.
Publication Type
Report
Date
September 1964
in this study agrees with those reported from other laboratories that myocardial substrate utilization is a function of arterial substrate concentration. However 1 prolonged reduction of myocardial temperature, with concomitant reduction in coronary blood flow, leads to diminished oxygen and
  1 document  
Author
Russ, C.
Lee, J.C.
Author Affiliation
Department of Physiology, Albert Einstein Medical Center, Philadelphia, Pennsylvania
Source
Arctic Aeromedical Laboratory. Alaskan Air Command. Fort Wainwright, Alaska. Technical documentary report, TDR-64-4. 9 p.
Date
September 1964
Language
English
Publication Type
Report
File Size
936167
Physical Holding
University of Alaska Anchorage
Keywords
Animals
Dogs
Cold exposure
Metabolism
Myocardial temperature
Hypoxia
Abstract
The effect of hypothermia of 25° C for 24 hours on myocardial metabolism and efficiency was determined on dogs fasted for approximately 15 hours and anesthetized with sodium pentobarbital. Coronary blood flow, cardiac output, myocardial oxygen and substrate utilization, and mechanical efficiency of the heart were determined at normal and reduced body temperatures. Prolonged reduction of myocardial temperature, with concomitant reduction in coronary blood flow, led to diminished oxygen and substrate utilization. Myocardial glycolysis began following 12 hours of cooling when pyruvate utilization stopped in negative balance. After 24 hours the heart stopped utilizing carbohydrates, with negative arteriovenous differences for these substrates (in the presence of normal arterial carbohydrate levels), but continued to utilize nonesterified fatty acid. The coefficient of oxygen utilization for the heart increased following 24 hours of cooling, suggesting a relative state of myocardial hypoxia. The appearance of hypoxia and glycolysis during the late hours of cooling suggest that the heart's limit of tolerance to cooling was near.
Notes
UAA - ALASKA RC955.U9 no.64-4
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